I intend to write an application which would be used by third party backup applications to freeze Exchange/SQL before taking a backup. Once the backup is complete then the third party backup application will call the unfreeze api from our app that will resume exchange/sql. We intend to do the above using VSS. Can anyone please shed some light on the same.
Also can anyone please provide me the link to VSS SDK Documentation. I am unable to get it. I have VSS SDK 7.2.
If this is not the correct site for this post kindly let me know which is the correct one in case you know.
This question would be more appropriate on the ntdev list, or even in
the Microsoft news groups.
I’m not sure I grasp what you are trying to do here. All backup
programs for Windows have to use VSS in order to create a snapshot
they can backup. Any backup product still using legacy mechanisms
can not get logo’ed. The last several versions of Exchange and SQL
have had VSS writer components in them to take care of quiescing for
data flush on backup and restarting databases after restore.
The design you give won’t work as you wish. The time between using
VSS to freeze applications and generating the snapshot to be backed
up has to be within the order of 10-30 seconds, after which the
volumes must be unfrozen. The backup application uses the handle to
the snapshot to read data whilst the file system resumes using a copy
on write approach as data is modified.
As for Exchange, you may be trying to bite off way too much
here. There are problems still to be solved in correctly backing up
an Exchange system. Not only do you have Exchange and its databases,
but you also need to take in to account that Exchange stores large
amounts of data in Active Directory. The Active Directory database
will be on the Domain Controller and this may not be the same machine
as the Exchange server. Add that the DC, and possibly the Exchange
server are also often clustered and you have problems that compound each other.
I intend to write an application which would be used by third party
backup applications to freeze Exchange/SQL before taking a backup.
Once the backup is complete then the third party backup application
will call the unfreeze api from our app that will resume
exchange/sql. We intend to do the above using VSS. Can anyone please
shed some light on the same.
Also can anyone please provide me the link to VSS SDK Documentation.
I am unable to get it. I have VSS SDK 7.2.
If this is not the correct site for this post kindly let me know
which is the correct one in case you know.
Thanks Mark for the reply.
All backup programs will use VSS on XP and ahead OS, right? Also on which OS will the backup apps not get logo’ed if they dont use VSS. Is it on Vista or also on 2k3 and XP.
Actually what we are trying to do is there was a backup vendor who was using some third party app for freezing and resuming Exchange/SQL. I suppose it was not using VSS. We were trying to figure out if we can do the same using VSS. One api support to freeze and the other to thaw. The IVssBackupComponents::DoSnapshotset() generates the freeze and thaw events in the writer. But it also takes the snapshot. So we were trying to figure if there is some way by which we can trigger the freeze event in the writer. Then the backup app will create the snapshot and then we will trigger the Thaw event in the writer. Please check the following link:
Thanks!)